Process for producing two-color effects on skins or furs



Patented, 7, 1937 UNITE- STAT ES- PATENT OFFICE T 2,101,696 I r traocass roa raonucmo Two-coma EFFECTS ON SKINS OR FURS HeinrichWagneniiiannheim, and Max Zabel and Alfred Ensslin, Dessa assignors toGeneral 11 in Anhalt. Germany, Aniline Works, Inc., New

York, N. Y., a corporation of Delaware 4 Claims.

Our present invention relates to a process for Y dyeing skins or fursand more particularly to such a process which produces beautiful andpermanent two-color effects on the said materials.-

One of the objects of our invention comprises the pretreatment of theskins and furs which are to be dyed in two-color effects. Another objectis'a method for producing pelts having white tips.- v 10 Further objectsof our invention may be seen from the detailed specification followinghereafter.

White-tipped furs have been produced essentially by either oftWomethods. By one of these 1d the fur is treated in a solution of alead salt and then in a solution of alkali sulfide or polysulfidewhereby, according to conditions, brown or black lead sulphide isprecipitated on the hair of the pelt. To produce the white tips the peltis super- 20. ficially painted with an acid solution of hydrogenperoxide which bleaches. the lead sulfide to lead sulfate. By the othermethod, to the parts of the pelt which are to remain white there isapplied by means of a coarse or fine brush a certain.

paraiiin mixture in moltenv condition and then the pelt is mordanted inthe usual manner and dyed with an oxidation dye. The paraflin reserve isthen removed by means of warm water.

Now we have found that beautiful white and 30, variegated effects can beproduced on skins and furs by a specific pretreatment of these materialsbefore dyeing. This pretreatment comprises the following procedure:-

The pelt which has'been softened and killed 36 in the usual manner, istreated with a chromium mordant- Then a solution of an alkali metalcarbonate or bisulfite, which may be thickened if desired, is applied tothe pelt in order to remove the mordant at the tips or certain spots.

40 After the material has been thoroughly rinsed,

it is immersed in a bath of an oxidation dye which does not dye the tipsor spots thus treated, or dyes them in a color other than that of thehair still containing the chromium mordant. These white or variegatedeffects can be improved by a reducing bleaching bath. i,

As compared with the lead sulfide method associated with the danger ofpoisoning by lead Application November 26, 1935, Se-

Germany December 15,

there is the advantage of a simpler operation,- more easily applicablein practice.

The following example illustrates the inven-' tion:

An unshorn lambskin is killed in a solution 6 containing per liter 3grams of calcined sodium carbonate and 5 cc. of ammonia solution of24per cent. strength for 2 hours at a temperature of 24 C. and is thenrinsed in the usual manner and freed from adhering alkali in an acid 10bath. The skin thus treated is laid overnight in a bath containing perliter 2 grams of potassium bichromate, 0.5 gram of tartaric acid .and.grams of common salt. It is then centrifuged, stretched and painted onthe places to .15-

be reserved .with a'solution, .containing per liter, 100 grams ofcalcined sodium carbonate, 50 grams oi potato starch and 20 grams of afiber protective agent descdibed in German Patent No. 480,898, thissolution being applied with a brush. 2o After several hours the skin iscarefully. rinsed; to remove the paste and dyed in a bath of thefollowing composition per liter: 2 grams of a mixture of 40 parts of thecompound made by dissolving 1 mol. 2.7-dihydroxy-naphthalene and 255 2mols 3-chloro-lA-diaminobenzene in alcohol and evaporating the solvent,60 parts of a dispersing agent and 2 cc. of hydrogen peroxide of 30 percent. strength, the liquor ratio being 1:750. After dyeing for 20minutes at'28 0., the skin is 30 removed, carefully rinsed and bleachedfor a. quarter of anfhour in a bath containing, per liter, 3 grams ofzinc salt of formaldehyde-sulfoxylate and 1 cc. of acetic acid of 30.per cent. strength.

white tips. 4

If instead of the oxidation dye prescribed above there is used theanalogous product from 1 mol. LS-dihydroxynaphthalene and '1 mol. meta-The products enumerated in Table B likewise.

yield twocolor effects with a. coloration of the tips or spots otherthan that of the parts still containing the mordant.

In these tables certain of the dyeing materials (marked by brackets) donot constitute mixtures; i

There is obtained a deep grey-brown ground with 35 toluenediamine thereis obtained, by the same 407 Table A Coloration oi- Dye preparation Thetips The imor spots respectively 1 2.6-dihydroxynaphthalene +4-eminodihen lamin p MmoL) Grey White +1.4-dieminobenzene 22.6-dihydroxynephthalene +4-aminodi henylamin e P mom Gre White+chl0ro-4-emlnodiphenyiamine (14 3 3 2.7-dihydroxyna hthelene+4-aminodip enylamine Grey White LS-diaminonephthalene 42.7-dihydroxynephthale11ie 1) mo +2-chl0r0-lA-diemino enzene Grey i (2moi.)

5 2.7-dihydroxy'na hthalene +2-chloi-o'1. obenzene 52.7-dihydroxynaphthalene +3.5-diemino-4-methoxy- Brown Whitel-rnethylbenzene 7 .2.7-dihydroxynepl thalene +1-methyl-2A-diamino-Brown White benzene g zJ-dinydroxynaphthalene +8-aminoquinoiine whlte 92.5-dihydroxynaphthalene +3.5-d1amino-4-chlor-l- Brown White'methylbenzene 10 3.5.8.10-tetrahydropyrene K +2.6-diaminonaphthaleneknown white 2 11 Lfi-dihydroxynaphthalene +8-aminoquinoline White 122.6-dihydroxynaphthelene +1.5-dieminonaphthelene m 13 Lfi-dihydroxyne.hthalene +benzidine p P 14 1.5-dihydroxynaphthalene+l.5-diaminonaphthalene' white 5 1.5-dihydroxynaphtheierie+2-emino-1-(dimethylemi- Red White no)-benzene 16 Lb-dihydrexynahthslene +4-am1nodip enylamine-Zi- Violet-brown White sulfonic acid 17LG-dihyglroxynaphthalene I +1-(dimethylammo)-2-chlor- Violet-brown White4-aminobenzene 18 1.7-dihydroxynaphthalene 1.3 dieminobenzene or iBlack-brown White methyl-ZA-diaminmbenzene 19 LB-dihydroxyneplrthaiene+2-dimethylammo-4-amino- Red-brown White l-chlorobenzene 201.4-dihydroxybenzene-2-phena ylsulione-hlA-diaminoben- Red-brown Whitezene 21 Dimethylgallic acid Beige White 22l.3-dihydroxybenzene+2.2'-dlamino-LY-dinaphthyl white Table B Colorationoi- Dye preparation The ups The fur spots tospectlvely 1 1.5 dihdroxynaphthalene ZA-dieZIlnQ-I-nitwbenzene Yellow 21.6-dihydroxynephthelene+2 nitro-li-dimethyleminoquln- Brown-oliveYellow oline 3 1.5-dihydroxynaphthelene+lamino-2-dimethylamlno-4-Red-brown Yellow nitrobenzene 4 1.6-dihydroxynaphthelene+lamino 2-dimethylemino 4 Brown Yellow nitrobenzene -51.5-dihydroxynephthelene-l-4- amino-l-(methylethylemino)- }Dark-biueLight-blue benzene v 6 1.6-dihydroxynaphthalene-l-lmethylamino 2 ehloro4 Dark-violet Light-violet eminobenzene 7 2.6-dihydroxynaphthalene 1) mo+1-(dimetl1ylemino)-4-amino- Datk'gmm Llzm'mn benzene a2.7-dihydroxynaphthalene 2- amino4.6-dinitro-4'-(dimeth- Brown Pinky1amino)-diphenylemine 9 1.6-d1'hydroxynaphthalene 4- amino-2-chloro-l-(di1nethyl- Violet-brown Pink nmino)benzene 10 1.5 dihydroxynaphthalene1.3 3 di (dimethy1amino)- 4 Brown Light-red eminobenzene Y 11 2.7dihydroxynephthelene 2.4.9- triamino--i- (dimethyl- Brown Violeta1n1no)-diphenylamine l2 3.5.8.10-tetrahydroxypyrenei-aminodiphenylemine Gm From the example and from the tables it may beseen that many of pelt dyes are suitable for producing the two-colorefiects on the pelts pretreated according to our invention. It isobvious, however, that our invention is not limited to these specificdyes, and other oxidation dyes suitable for the same purpose areconsidered to be within the scope of the claims following hereafter.

What we claim is:--

1. The process which comprises treating a fur or pelt in a chromiummodanting bath, tipping or spotting the mordanted hairs with an agent ofthe group consisting of alkali metal carbonate and alkali metalbisulfite for removing the mordant, rinsing the pelt and dyeing it withan oxidation dye yielding difierent colorations on the mordanted andunmordanted places.

2. The process which comprises treating a fur or pelt in a chromiummordanting bath, tipping or spotting the mordanted hairs with an agentof the group consisting of alkali metal carbonate and alkali metalbisulfite for removing the mordant, rinsing the pelt and dyeing it withan oxidation dye which dyes only the mordanted parts of the pelt.

3. The process which comprises treating a fur or pelt in a chromiummordanting bath, tipping or spotting the mordanted hairs with an agentof the group consisting or alkali metal carbonate and alkali metalbisulfite for removing the mordant, rinsing the pelt, dyeing it with anoxidation dye which dyes only the mordanted parts of the pelt, andsubjecting it to a reducing bath;

4. The process which comprises mordanting a fur or pelt with an alkalimetal blchromate, tipping of spotting it with a. thickened solutioncontaining an alkali metal carbonate and thus re moving the mordant,rinsing it and then dye-.

ing it in an aqueous solution containing an oxidizing agent with theproduct, obtainable by dissolving "one. molecular part of2.7-dihydroxynaphthalene and two molecular parts of 3-ch10-ro-lA-diaminobenzene in alcohol and 1 evaporating the solvent, rinsingthe dye thus colored in two-color effects and finally subjecting it toa.

reducing bleach.

HEINRICH WAGNER.

MAX ZABEL. ALFRED ENSSLIN.

